docstr: The prefix token is the same as the end of text token.
docstr_tok: ["The","prefix","token","is","the","same","as","the","end","of","text","token","."]
code: def prefix_token(self) -> str:
      """The prefix token is the same as the end of text token."""
      # echo=True is not supported
      return ""
  
file_path: H2O/h2o_hf/helm/src/helm/benchmark/window_services/t0pp_window_service.py
imports: from .encoder_decoder_window_service import EncoderDecoderWindowService
  from .tokenizer_service import TokenizerService
label_desc: Use image node_id 6 for calling the T0ppWindowService obj's underlying member method code with example usage: obj.prefix_token() and returns: str